Conventional techniques for disposing an optical film in a frame of a backlight module are as follows:
A first method: studs are disposed on a back plate, and holes are disposed on the optical film corresponding to the studs, by having the studs going through the holes, the optical film is disposed and fixed on the back plate.
A second method: fitting grooves are formed directly on the back plate when it is manufactured, and the optical film is fitted in the fitting grooves so that it is disposed and fixed on the back plate.
A third method: the backlight module has an upper frame and a lower frame, and they have structures of hooks and grooves respectively with corresponding shapes, a structure is designed in one of the frames for disposing the optical film between the upper and the lower frames. The upper and the lower frames are tightly fitted together by the hooks and the grooves with corresponding shapes, and the optical film is limited to move, so that it is disposed and fixed on the back plate.
However, for the first method, the manufacturing procedures of the backlight module will be increased by the disposing of the studs and the holes, resulting in the production efficiency of the backlight module being affected tremendously. For the second method, burrs are usually generated on edges of the grooves when they are formed, and the optical film may be damaged easily from cutting by the burrs. For the third method of the upper and the lower frames, even though the optical film is effectively fixed, it is not possible for the backlight module to have a slim design, and the space for disposing other components is limited, and resulting in the quality of the backlight module being affected. Therefore it is necessary to improve the component structures of the backlight module, particularly the positioning components for the optical film.